1. Field of the Invention
The present invention relates to an image correcting camera capable of correcting movement of an image due to movement of hands at the time of photographing.
2. Related Background Art
There are known image correcting cameras which have an image correcting device for correcting movement of an image due to movement of hands at the time of photographing. When a vibration sensor provided in such a camera detects vibrations, the image movement correcting device drives a correcting lens provided in a portion of the photographing lens system to cancel the vibrations thereby to correct movement of an image based on the output of the vibration sensor while the shutter is opened.
FIGS. 7 and 8 are block diagrams showing structures of conventional image correcting cameras capable of correcting movement of an image as disclosed in Japanese Patent Application Laid-Open Nos. 3-37616 and 3-46642 respectively.
The camera in FIG. 7 is provided with angular rate detectors 23, 24, a correction drive amount calculating device 25 and a correction drive device 26.
The angular rate detectors 23, 24 detect angular rates (movements) around X- and Y-axes which are at right angles to the optical axis of the camera.
Based on the displacements (rotation angles) around the X- and Y-axis directions calculated from respective outputs of the angular rate detectors 23, 24, the correction drive amount calculating device 25 calculates an amount of drive of a correcting lens (not shown) so as to cancel the movement of the image.
The correction drive device 26 correct the movement of the image occurring in the camera by driving the correcting lens in accordance with the calculated amount of drive.
The camera in FIG. 8 is provided with acceleration detectors 27, 28, angular rate detectors 29, 30, an object distance measuring device 31, correction drive amount calculating device 32 and a correction drive device 33.
The acceleration detectors 27, 28 detect accelerations in X- and Y-axis directions respectively.
The angular rate detectors 29, 30 detect angular rates around X- and Y-axes respectively.
The object distance measuring device 31 measures the distance between an object and the camera.
Based on a displacement (an amount of movement) in the Y-axis direction calculated from the output of the acceleration detector 28, a displacement (a rotation angle) around the X-axis calculated from the output of the angular rate detector 29, and the output of the object distance measuring device 31, the correction drive amount calculating device 32 calculates an amount of rotation around the X-axis so as to cancel its movement. Similarly, based on a displacement in the X-axis direction calculated from the output of the acceleration detector 27, a displacement around the Y-axis calculated from the output of the angular rate detector 30, and the output of the object distance measuring device 31, the correction drive amount measuring device 32 calculates an amount of rotation around the Y-axis so as to cancel its movement.
In accordance with these calculated amounts, the correction drive device 33 rotates the optical system of the photographing device around the X- and Y-axes to correct the movement of the image in the X- and Y-axis directions.
However, in the above-mentioned cameras, there have been following problems.
In the camera of FIG. 7, since the movements of the camera are detected only by the angular rate detectors 23, 24, movements in translational directions cannot be detected. Therefore, it is impossible to correct the movement of the image produced by the movements in the translational directions. Particularly, when the photographing magnification is high, the movement of the image in translational directions of the camera are large, which causes the image quality to be lowered.
Also, in the camera of FIG. 8, movements in the translational directions of the camera can be detected by the acceleration detectors 27, 28, but since gravitational acceleration components acting on the acceleration detectors 27, 28 due to rotational movements of the camera are changed, the movements in the translational directions cannot be detected properly. Therefore, it is impossible to correct the movement of the image accurately, whereby a clear image cannot be obtained.